It was after HE ate that the eyes of both of them were opened.
The responsibility was Adam's. God gave him dominion over the whole earth. He was responsible for his family. He failed. The sin was his for disobedience. He did not protect her and chose to disobey God when he had no excuse as he talked with God himself.
A lot can be learned by simply reading the Bible. Life falls into place. Things make sense when our lives are aligned to His word. Men are the head of the household and men are responsible for the spiritual education of their family. When that order is denied or ignored, confusion and error follow.
That is correct. We'll have to watch the PCA to find out if they follow the same road as the Anglicans, Methodists, Lutherans, most Presbyterians...